Cataclysm
by sloangrey
Summary: Some say the world will end in fire, some say in ice. From what's been tasted of desire, she'll hold with those who favor the apocalypse. Part Three of the Trial by Fire Saga.


**Summary:** Some say the world will end in fire, some say in ice. From what's been tasted of desire, she'll hold with those who favor the apocalypse.

 **Warnings:** Language, as always, violence/torture on down the road. Brief moment of drug injections. Rating may go up in future chapters.

 **From Em's Notes:** Well well, here we are once again! I know I have certainly kept you all waiting for quite some time, but I figured there's no time like the present, right? Welcome back to what I've now dubbed as the _**Trial by Fire**_ Saga, because I don't think Swiftchanted's AU has that nice of a ring to it. Originally, I planned for this to be a trilogy, and the only reason I even kicked my ass into gear with the reboot of Lights Out was because of this very story right here — the Age of Ultron AU. Let me start by saying that this is an AU in the highest of degrees; there will be several elements from the film such as scenes and some plot points, but for the most part I'm merely using the movie as a structure and I'm filling in the holes how I so please. That means there's none of the Brucen*t cringe (sorry to those of you who like them!) no Barton family, and of course some surprises down the road. I've had this story brewing for quite some time and hopefully I'll be able to churn it out as fast as my fingers and schedule allow, so I hope with all of my heart that you truly enjoy this piece as much as the other two! I know it's definitely my favorite, even though AoU wasn't my favorite movie...well, ever. Don't forget to drop a review at the bottom!

 **Chapter One:** Flaws by Design

* * *

HYDRA was a bitter sting in the back of Katniss Romanoff-Barton's throat, which made her all the more eager to go after them with fires blazing and guns at the ready. Fortunately, she was in the right company, as there was a shared objective among them: blow HYDRA to kingdom come. Or straight into the ground, whichever proved to be most effective.

This was the fourth base over the past two weeks that they were storming through, all a part of the wild goose chase Thor had them spiraling along in hunt for Loki's misplaced scepter. It baffled her, how that had gotten out of Nick Fury's sight to begin with, but Katniss supposed it was hard to watch everyone and everything with only one functioning eye. The Avengers were all in solid agreement on one thing: the scepter was in the wrong hands if it wasn't in theirs.

"Hand me the exploding heads?" Clint's voice entered her realm, calm and steady as she went about polishing her bow. Using a spare hand, she bent down and grabbed the box that contained the more theatrical arrowheads out of their arsenal, a small box with a strip of masking tape on the side with a label that simply read, ' _Kaboom.'_

"Pass me my old glove, this new one is still getting on my nerves," she replied. A strangled noise came from somewhere in the Quinjet, and Katniss didn't have to look up to know that it was Tony.

"Excuse me, but I made that glove out of love, goddammit. You better learn to love it." Tossing her hair over her shoulder, Katniss glared up at her godfather.

"When you become an archer and understand the concept of balance, let me know."

Tony glanced down at Clint, who was currently trying to organize his arrowheads and not add his input to their debate. "At one point, I would have thought you and Romanoff having a child would be a wonderful thing, but I'm starting to realize that maybe it's my biggest nightmare realized. I mean _really_ , did you name me godfather knowing she'd make my life a living hell? Do you not feel any remorse?"

Clint merely smiled. "That's my girl."

"Steve could probably fight you on that one," came Bruce's thinly veiled laugh. Sitting over in the corner holding both his knees to his chest, Katniss offered him a small smile. The past few weeks had been rough for Bruce; transforming always seemed to do him in, and as frequently as he'd been doing so was starting to wear away at him. She didn't understand why he continued to insist on following along when it was plain as day to the rest of the team that he was beginning to feel the repercussions of Hulking out on command.

"Steve would do no such thing, because that's a fight he'll lose ten times out of ten." Katniss had to stifle the chuckle under her breath at her father's sudden irritability.

Tony was persistent in rerouting the conversation back to him and the disparagement of his creations. "Seriously," he whined. "The Avengers have never looked better, and it's all because of me."

"Is that a gray hair I see?" Natasha sang as she moved past him, the smirk on her face much too delightful. "You claim you've done so much for the Avengers looking better, but you still look like you're one foot in the door of the old person's home."

"Clinton, contain your wife, please, before I do something I thoroughly come to regret." Clint shrugged half-heartedly, the knowledge that restraining Natasha was a foolish dream at best and Tony was stupid for still having to come to that same conclusion. Words continued to fall from Tony's mouth as he gestured around the Quinjet at the group.

"Look around, Red; we've gone from costumed crusaders to stylish superheroes. We've all upgraded. Steve's suit is bluer than it's ever been before, to draw away from the pollution destroying our atmosphere—"

"Relevance?" Steve interjected, raising his hand.

"—Raggedy Ann over there's rotated hair styles yet again—"

If her eyes were in any way weaponized, Natasha would have set Tony ablaze there on the spot. "Clint, if you wouldn't mind, give me an arrow so I can shove it through his _jugular_ —"

"—and baby bird's gone from baby bird to Mockingbird, her new little codename. Obviously paying homage to her favorite godfather." For emphasis, Tony reached down in attempt to ruffle the top of Katniss' hair, and she saw the gesture coming a mile away.

"It's Mockingjay, dipshit," she corrected as she ducked out of the line of fire.

The grin on Natasha's face could have put the Cheshire Cat out a job. "You're right Stark, I do love these upgrades. My daughter calling you a dipshit just might be the highlight of my year."

"I thought yours and Barton's annual getaway sex-cation was the highlight of your year."

"Clint—"

"You are _not_ wasting my arrows on him; ask your kid. She favors you anyways."

"Can we focus on the actual problem at hand, the one that isn't Stark's never ending flow of commentary?" Steve interrupted, trying to reroute everyone's attention back to their mission. Tony finally fell silent, not without a final huff before Steve was able to continue.

"There are two things that we know for certain. HYDRA's set up base on the castle, and that the scepter's been tracked at this location."

"Are we right to assume that HYDRA's been their usual standard of moron and haven't relocated the scepter?" Clint asked, gesturing around. "I mean, we're not exactly the slip in and out without a sound type, and if HYDRA knows we're looking for it, they're going to be on the defensive."

"Which is why we're switching it up and playing offense," Tony interjected gleefully. "We're using the forest to our advantage; Capsicle and Baby Bird are going to be coming in from the west, Blackhawk the east, and Thor and I are airborne. We'll pop in where we see fit." Thor, who had possibly no proper inkling of what _'popping in'_ meant judging by the grand entrances he made each time he returned to Earth, nodded fervidly.

"And Bruce?" Everyone's eyes wandered over to him, looking at him expectantly. He immediately perked up, glancing around in confusion.

"Huh?" Katniss shot him a look. "Oh. Right, um, I'm not sure if we're calling a Code Green on this one, guys…this will be the third time this week, I'm not sure if it's, you know, the _best_ idea."

Well, at least he was now finally admitting everything had caught up with him.

Tony, the _least_ helpful person in the situation, took it upon himself to insert his two cents into the debate. "No one tears it up like you, Big Guy," he encouraged, reaching over and nudging Bruce in the elbow with his shoulder. "Besides, HYDRA kind of deserves a beat-down, if you ask me."

"Fortunately for all of us, we didn't," was Natasha's smooth reply. "Bruce goes if we find it necessary. After all, you're not his handler." A smug smile spread over her mouth as she framed her face with one of her gloved hands. "I am."

It wasn't much of a secret that the Hulk was viewed as a threat and he was treated as such, something that Bruce had pushed their hand into doing out of the fear he'd hurt someone. Just like Inferno had been put into place for Katniss a few years ago, Bruce had been assigned a contingency plan that followed much stricter terms and kept him on a very, very short leash with Natasha at the helms. She was, after all, the most responsible on the team. No matter how accommodated he got to modern possessions, Steve was still in his nineties, Thor was fascinated by mundane items such as a toaster, Tony had been deemed 'off the rocker' years ago, Clint might as well have been five years old, and between her various physical ailments and ridiculous temper, Katniss couldn't keep her own if the Hulk decided to go after her. She was the only eligible team member.

Tony rolled his eyes, falling back into his rotating chair and spinning back around towards the windshield of the Quinjet as Bruce shot Natasha a quick look of gratitude. "Whatever, Red. I can't _wait_ to pull out the old, 'I told you so' on you when the time comes."

"I'm sure you can't."

"Kat, injection," Steve called out in reminder, unsnapping the latches on a box hanging on the wall as all the oxygen seemed to vanish from the atmosphere and was replaced with silence. Her legs hadn't improved any over the last two years; instead, they only seemed to grow worse. Staying off of them for as long as possible ensured that she got as much performance out of them as possible, and Bruce had her on steady rounds of steroids before missions in order to guarantee they wouldn't fail on her. Being born with a bit of Natasha's genetically mutated code meant her body took to things much differently, and the steroids helped numbed any pain she felt up until the meds wore off. It was one of the unspoken yet obviously controversial things milling around in the Tower's conversation box, and even as Steve pulled out the syringe, things got quiet on the Quinjet, much too awkward for regular discussion to resume. Clint was now looking at the floor and Natasha was suddenly mighty interested in her palms.

Katniss had already pulled out the thin strip of cloth that they liked to use as a tourniquet, Bruce's method of effectively getting the juice in her faster as she apparently had very reedy veins. Wrapping it slowly around her upper arm, she started to pull it tighter, restricting circulation to make her vein more accessible. Eventually the cloth made its way in between her teeth in order to obtain the tightest cut possible, at which point most of them had stopped paying attention as best they could. Steve, however, approached her with a smile on his face.

He removed the cap with his teeth, holding it there as he reached out for Katniss' arm. She extended it without a word, lips pressed together firmly and head turned in the opposite direction while Steve did his part, just like they were used to. It had become a routine, the two of them doing this on missions when they were with the team or flying solo, on the hunt for Bucky. Steve didn't ask questions, a rare thing seeing as how he usually had the most.

The injection was done in moments, Katniss quickly wiping the place where the needle had been down with a cotton pad and rubbing alcohol down in a fluid motion. Steve disappeared, back to his respective side of the Quinjet, still a heavy silence hanging over everyone. Much less strained, but there was still a substantial weight pressing on her shoulders.

"What if one day while you guys were doing that, we hit an air pocket and got thrown all out of whack?" Tony muttered.

Katniss strolled behind him, grin on her lips as she rested both hands on the back of his chair. "Guess that means the mighty Tony Stark tech isn't as durable as he proclaims, huh?"

He merely huffed in response. "Landing in ten."

 **. . .**

HYDRA was a bitter sting, but they sure were a bore. Predictability seemed to be the only thing they had a true grip on; that, and the whole evil villain thing that had grown overdone the longer she did this. They were more of a joke with a good bit of muscle on them, but their muscle came in heavy numbers. Like little plastic army men, pouring in by the waves with only one order: destroy. She mocked Pierce's voice in her head with what seemed to be the ridiculous mantra they followed, ' _you have to create chaos in order to pave the way for peace_.' Bullshit was what it was.

Snow crunched under her feet as she maneuvered swiftly through the trees, bow drawn and her index finger and thumb rolling the arrow as she watched for her next target. Of course, HYDRA had settled on their white-toned uniforms to help blend with their surroundings, according to Clint's handy intel. Splitting up gave them the advantage; it was easier to know what to look for once someone caught sight, but it also sent up giant flares towards their presence.

Katniss and Steve had split up beyond their division from the rest of the team; Katniss was to find another way into the castle while Steve did a remarkable job at distracting the muscle. The two had shared a brief moment before Steve sped off on his motorcycle, one that probably wouldn't last any longer than the other four motorcycles Tony had made for him. He had a habit of using them as large weapons of mass destruction.

"Gonna be okay?" he'd asked quietly, forehead pressed against hers. He was warm in the cold of Sokovia; then again, Steve was always a furnace. His eyes had been locked on hers, even as hers were focused more on their proximity to one another, the small details in the navy blue of his combat suit.

They weren't a couple again, per se, instead it seemed they'd fallen into the same sort of relationship that Clint and Natasha had. Intimate moments were behind closed doors, far away from the rest of the world, and the minute things got serious, the power was cut and the only time there was ever any evidence they felt anything deeper was if someone looked for a few moments longer. They were partners first and foremost, and everything else was merely a cloud over the city. Everyone in the Tower had stopped asking about it as well; they would either see a name change or someone would move away in the heat of the moment and that would give them a definite answer about the status, and everything in between was clearly none of their business. Despite Tony's attempts to wire new cameras in their rooms to pry into their personal lives, Katniss had enlisted the help of a Natasha _burning_ to torment Tony in any way she could to override them and make sure that the only image Tony ever saw coming from Katniss' room was one of her dead asleep on the bed. He'd asked many questions about it, and Clint had merely laughed when he came looking for answers.

Katniss had nodded, taking a deep breath. "Yeah, I'm fine," she whispered. The edges of her lips turned up as an offering of a smile, grey-green eyes glancing up at him to solidify her words. "Kick some ass."

"Stay alive."

He'd squeezed her hand, their parting moment nothing more than a tangle of hands that did their best to get a solid grip on the other, a transfer of feelings the both of them would never be able to put into words even in the frigid weather, before he pulled the motorcycle off the tree he'd propped it up against and jetted off into the snow.

Now her only mission was to keep her eyes peeled – for what, she was uncertain, perhaps an entrance or some kind of key on getting in without sending up every warning notification there was up HYDRA's sleeve. Instead, it was snow around snow piled around trees around more snow.

"This is a bust," she muttered through gritted teeth.

"Well I'm glad you seem to think so!" Steve shouted loudly through the comms, what seemed to be an entire commotion of the battlefield stirring in the background of the feed. "Wanna trade places?"

Even though he couldn't see it, the smirk on her face was wide enough to be heard through the transmission. "Nah, I'm good with my bust."

At some point in her life she'd learn not to eat her words, but that day wouldn't be today. The words had barely left her mouth before her eyes caught the blur move past her, the wind following in its trail. Her sight had gotten better at the loss of her hearing, and if she was seeing things, then that was a sign the steroids weren't exactly what she'd been promised when Bruce had loaded them before their departure from New York.

Whizzing back by her, she caught the silver glow in the streak that passed by her, almost encircling her for a teasing moment before sailing off towards the forest where the gunfire and explosions were distant.

"Guys," she started hesitantly. "I don't think we're alone."

"Specify!" Natasha barked in response, her voice on the breathier side.

"We have a…something," Katniss stammered into the comms, still bewildered at what she'd just seen.

In her ear, Clint groaned. "Enhanced."

"Clint's hit!" came Natasha's voice over what sounded like more gunfire. Joyful; that only meant Bruce would be put into play even harder.

"Would it kill you not to get injured every damn time we leave the compound?" Tony retorted, and the feral growl that had to have come from Natasha was enough to shut him up quick. He didn't have that strong of a death wish.

Katniss looked back in the same direction as the silver blur had come, what seemed to be a black spot in the midst of the entirely white wonderland they'd planted themselves in. Curiosity would always get the better of her, of course, and she began to approach it with an ounce of caution, that way she could say she'd at least been careful when all of this came to bite her in the ass.

The closer she got, she realized it was a tunnel, cogs in her mind whirring as they tried to add two and two together. The only solution she could come up with was that this tunnel lead into the castle, and she was willing to follow that hunch.

Inside was dark and chilly, the faint sounds of melting ice and snow dripping and the crunch of her boots on the ground echoing through the halls. It was times like these when she wished she had Tony's suit or just a flashlight strapped to her head, a means of helping her maneuver in the dark. Sure, her sight had gotten better, but that didn't automatically qualify her as a night-vision expert. In her ear, the comms were still alive with conversation; Katniss chose to keep quiet and instead use the voices as a form of company, carrying her through what seemed to be a never-ending hallway.

An end was inevitable, and she hadn't expected to run straight into it, but she had. The sound of her body colliding with what felt like a wooden door left a solid thud bouncing off the walls, a wince settling over her face. She felt around in the dark for some means of opening it, pushing against it to only no avail. Her hands brushed over an iron door handle, testing it both push and pull with the same results as before. Drawing an arrow from her quiver, she knelt down to what she felt was eye level to the lock and used her fingers to carefully feel for a hole that was a sign of entry, jamming the entire arrowhead into the slot after pressing a small button on the side.

In her head, she counted down from three, and one small explosion later, the door was willing to be opened.

Dimly lit and dank quite like the tunnel had been, save of course for the empty window holes, the inside of the castle did more reflecting of its age than the outside architecture did. Voices seemed to float – from where, she was unsure, but she couldn't be too careful. She kept to the walls, bow wound in between a tight fist as she prepared herself for any possible ambush. Last she'd heard in the comms conversations, Tony had supposedly taken the castle, but she had no idea how much of a labyrinth this place would be.

Eyes darted around, her free hand moving along the texture of the wall trying to feel for Tony's favorite, secret doors. A castle this old had to have a few secrets lurking in the shadows; her godfather would be highly disappointed if there weren't.

She wasn't sure how long she aimlessly trailed around the halls; the castle had seemed colossal on the radar but wandering within its walls only amplified its size. Hope had all but been lost and she was veering on the edge of calling for Tony and potentially compromising her position when she found an abandoned room, taking a detour and following into it.

It seemed relatively empty, like it hadn't been occupied even after HYDRA gained control, which made her logic of their hiding spots being in blatant places even stronger. She began to feel around the walls, pushing in various places all while trying to watch the open entrance. Her hunt had almost been named futile and credit had almost been returned to Pierce's little army up until she hit a loose spot, shaking a brick loose in the structure and a panel on the opposite wall revealing itself. She grinned. Tony would have been proud.

As she entered, the first thing she noticed was the lack of light. The room was even darker than the halls, scrap parts scattered all over the work tables and floors. It vaguely reminded her of one of Tony's labs back in his insomnia-ruled phase when he spent every night and every day in a lab that quickly turned into Hoarders material, with a lot less light and a lot more clutter. Bars covered the open ceiling and with as much dust occupying the room, the air was thick and uncomfortable. No wonder it had been abandoned; had she worked for HYDRA she would have ditched this place the second she was given opportunity. The deeper into the vault she went, the more horrified with its contents she became, nearly giving herself a heart attack when she laid eyes on something she hadn't seen in years, a memory that had become just a memory and was now staring her back at the face. There was one of the Chitauri's Leviathans, sitting immobile, probably having been used for HYDRA experiments.

Spooked and now slightly hesitant to venture farther, Katniss swallowed hard before continuing on into the depths of the room. If she knew HYDRA to be anything, it was somewhat obvious. There was more clutter, abandoned tests and experiments and projects as décor. She watched her footing carefully as she walked down the few steps leading behind the framed Leviathan, head peering around a corner only to see exactly what it was they'd come for.

Crackling with electricity around its stand was the scepter. One look at it and a whole other tidal wave of memories with bad tastes in her mouth hit her square in the chest. God, did she hate that thing.

"Guys, I found it," she said quietly, her voice still reverberating off the walls as she drew closer, her legs almost carrying her towards it on their own accord. "I have the scepter, does anyone copy?"

The comms were silent, unusual considering her teammates and their knack of long, dramatic monologues to no one in particular (read: Thor), and Katniss' eyebrow furrowed as she brought her finger into her ear, pressing the unit harder to absorb as much sound as possible. "Mockingjay, _does anyone copy_?"

The comms weren't working but she distinctly heard the thud come from behind her, Katniss whirling around on instinct as her arm jutted back for an arrow in her quiver. That hand fell slowly when she realized what the noise was; it was the Leviathan, shaking loose from the steel bars holding it upright like some sort of fossil on display. The bow clattered to the ground as it slipped from her hand, her eyes frozen open in horror as she watched it slip through the air like a snake might, the movements all too familiar and jarring from a memory she'd done well to block off.

Grey-green eyes now clouded with trouble followed the beast, up into an eerily blue sky. She could see all of the stars, Earth now off in the distance of the clouds as hundreds of Leviathan floated in the air, their destination clear. The sight knocked the wind from her, bringing her straight to her knees on the dusty floor. Instead, her view was now replaced with the surface she rested on, a giant silhouette with an arrow sticking straight out of it obstructing the Leviathans and their descent onto Earth. Her stomach lurched when she realized that silhouette was the Hulk.

All around her they came into view, all lifeless and some impaled by the Chitauri's weapons, broken and battered and completely helpless now; Natasha and Clint only a few inches shy from one another, their fingers barely brushing as they reached out for one another even in death, Thor's cape wound tightly around his neck and a much darker shade of crimson than she knew it to be, Tony with the metal of his suit sticking out of him and a fear in his eyes that had been there just before life was stripped from him, Steve and the broken shield lying off to her right in a heap. And then there right in front of her was another figure, gasping to breathe – lungs more than likely filling with blood – and reaching out for her.

Katniss looked down and immediately wished she hadn't.

"Gale," she breathed, struck with horror. He hadn't haunted her in quite some time, and this was probably penance for that very thing. "Gale, oh my god, are you okay?"

Gale found the last bits of energy pent up inside him and grabbed her arm, startling her. The light in his eyes was slowly fading; he was teetering on the edge of death. She gingerly grabbed his hand, trying to pry it from her limb only to come away with a crimson-stained hand. Nausea hit her full force as she came to realize she was kneeling in a pool of his blood. "Could've…saved…me…" Each word took everything in him to utter out, eyes never leaving her face.

"I'm…Gale, I'm s-sorry," she stammered, hands resting underneath his jaw. There was hardly a pulse left, and it was clear he was barely clinging to whatever frays of life that had stayed strung together in a thread.

She'd never get to see the light fully leave his eyes. Just like that, the breath was sucked right out of her gut, a vacuum forcing the air to leave her body. Eyes wide, her hands gravitated towards the one place that was now inhabited by a foreign object. A pair of larger, much tougher hands had wound around her throat and it was clear the objective was to wring her out like a sponge. The tears formed in her eyes as she desperately sought to break free, throat scorched and choking out what little gasps of air she could manage.

It forced her off of her knees, hands clawing at the iron grip around her neck. Words refused to leave the back of her throat, the panic burning her skin as she felt her feet leave the ground. It was only her, dangling in the air and clinging to her captor in a final attempt to tear loose before all movement ceased. Black spots were already forming in her vision, and what an ironic thought it was that this was the lesser of two evils: the life being choked out of her much more enjoyable than watching the people she loved die in front of her eyes, by her hand.

The voice in her ear was a steel melody; the touches of familiarity send shivers down her spine as they crooned, singing her demise for their own sick entertainment.

"I can't wait to watch you _snap_."

"Kit-Kat?"

The oxygen entered her lungs in a sharp inhale she hadn't been aware of stealing, and her surroundings came flooding back to her like a tidal wave. Tony stood in front of her, face a blank slate as he stared quizzically, trying to get a read on what was going on. Her breathing started to calm, eyes meeting his slowly. It quickly registered to her that he hadn't seen a damn thing that she had, that he hadn't an inkling of an idea that she was dying. No, she'd been dying, but only within the confines of her own mind.

She wanted to fling her arms around his waist, but instead she reached for the scepter.


End file.
